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I'm undertaking a fairly simple workflow all within a python script with the goal of passing urlencoded GeoJSON in a URL to the Mapbox static API:

  1. create a point from DD string in EPSG:4326:
  2. convert to UTM for easier units and buffer the point generating a polygon
  3. transform back to WGS84 for the API
  4. generate valid, URL encoded GeoJSON string.

My hangup is the last part. I've used Shapely and pyproj to conduct 1-3 but using:

json.dumps(mapping(<shapely.geometry.polygon.Polygon at 0x106a22690>)) (and several permutations of this) and encoding it using urlencode or url_quote generates an encoded URL with JSON that returns 'Invalid Geojson' from Mapbox.

I am optimistic that the geojson library may solve this, but I can't seem to find a simple way to convert a shapely Polygon object to a GeoJSON polygon object.

nmtoken
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PeterT
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  • Without a real example, we can do nothing an json.dumps(mapping(<shapely.geometry.polygon.Polygon at 0x106a22690>)) is not a correct formulation – gene Oct 10 '16 at 18:05
  • apologies and update: geojson.dumps(mapping(poly)) where poly is a valid shapely polygon geometry generates valid geojson. my challenge at this point is to encode it in such a way that the mapbox api doesn't reject it. – PeterT Oct 10 '16 at 18:17
  • look at Mapbox: Add a GeoJSON polygon – gene Oct 10 '16 at 18:29
  • thanks @gene I'm working with the static API. just tried the mapbox-sdk-py as well and get a 422 server response with valid python geojson object... this feels like it should be easy. I must be missing something... – PeterT Oct 10 '16 at 19:40
  • http://gis.stackexchange.com/questions/41465/generating-geojson-with-python check this link out – ziggy Oct 10 '16 at 22:03

1 Answers1

2

Decided to use the mapbox-sdk-py library instead. Works well but the pipeline from shapely to a map-able feature using the SDK is a little cumbersome (per this issue)

Need to add some features to the shapley (geom, below) object and encapsulate it in a list:

feature = [{'type': 'Feature', 'properties': {}, 'geometry': mapping(geom)}]

for the Static method to work.

Thanks @perrygeo and @sgillies for the hints.

Community
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PeterT
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  • What way is to avoid sequence of tuples in coordinates? It returns in mapping(geom): 'coordinates': ((37.353705999999995, 55.98468299999999), (37.353929229834065, 55.98471677959936),... I would like the native sequence of lists instead – Jane Nov 21 '19 at 09:06